Support priority based dumpsys in surface flinger

Call dump with no args when called with CRITICAL priority. Register
service with support for critical priority dumps.

BUG: 31774394

Test: lunch mini_emulator_x86-userdebug && make -j56
Test: adb bugreport ~/tmp.zip
Test: adb shell dumpsys --priority CRITICAL
Test: mmm -j32 frameworks/native/services/utils && \
      adb sync data && adb shell /data/nativetest/prioritydumper_test/prioritydumper_test && \
      adb shell /data/nativetest64/prioritydumper_test/prioritydumper_test && \
      printf "\n\n#### ALL TESTS PASSED ####\n"

Change-Id: Iec35ef8026d4d9346c83bab203bed8524c28bf89